Image Formats Explained: PNG vs JPG vs WebP (and When to Use Each)

Choosing the right image format is one of the easiest ways to make your website faster, your downloads smaller and your photos sharper. Pick the wrong one and you either bloat your page with huge files or throw away quality you can never get back. This guide breaks down every common format, why it behaves the way it does, and when to use it.

First, two ideas that explain everything

Almost every difference between image formats comes down to two simple concepts. Understand these and the rest is easy.

1. Raster vs vector

Raster images are made of a grid of coloured pixels (JPG, PNG, WebP, GIF, AVIF). They look great at their native size but become blurry or blocky when you scale them up. Vector images (SVG) are made of mathematical shapes, so they stay razor-sharp at any size — perfect for logos and icons, useless for photographs.

2. Lossy vs lossless compression

Lossy compression (JPG, and the lossy mode of WebP/AVIF) permanently discards detail your eye is unlikely to notice, producing much smaller files. Save the same JPG repeatedly and quality slowly degrades. Lossless compression (PNG, GIF, and the lossless mode of WebP) shrinks the file without throwing anything away — you can re-save endlessly with zero quality loss, but files are larger.

JPG / JPEG — the format for photographs

JPG (also written JPEG) is the most widely used image format in the world. It uses lossy compression specifically tuned for photographs: it breaks the image into blocks and discards subtle colour and brightness detail the human eye barely registers. That's why a 6 MB camera photo can shrink to a few hundred kilobytes with no obvious difference.

Why use it: excellent compression for complex, colourful images like photos; supported by every device, browser and app ever made.

Watch out for: no transparency support, and it's lossy — repeated edits and re-saves cause "generation loss." Sharp edges, text and flat colours get fuzzy "artifacts," so it's a poor choice for logos or screenshots.

When to use JPG: photographs, complex images with many colours and gradients, email attachments, and anywhere broad compatibility matters more than perfect edges.

PNG — graphics, transparency and pixel-perfect quality

PNG is a lossless format built for graphics rather than photos. Because it never discards data, lines stay crisp, text stays sharp and you can re-save as often as you like. Crucially, PNG supports an alpha channel — true transparency — which is why logos and overlays are almost always PNG.

Why use it: perfect quality, transparent backgrounds, and great compression for images with large areas of flat colour (logos, icons, diagrams, UI screenshots).

Watch out for: file sizes for full photographs are far larger than JPG — often several times bigger — because lossless compression can't take advantage of the "good enough" tricks JPG uses.

When to use PNG: logos, icons, illustrations, charts, screenshots, any image that needs a transparent background, and graphics you'll keep editing.

WebP — the modern all-rounder for the web

Developed by Google, WebP is a modern format that does almost everything: it offers both lossy and lossless modes, supports transparency and animation, and produces files roughly 25–35% smaller than the equivalent JPG or PNG. For most websites it's the best default today.

Why use it: smaller files than JPG and PNG at the same visual quality, with transparency and animation in a single format — faster pages and better Core Web Vitals.

Watch out for: while all modern browsers now support WebP, some very old software and a few print workflows still don't. Keep a JPG or PNG fallback if you need to support legacy tools.

When to use WebP: images on modern websites and apps, product photos, hero images, and anywhere you'd otherwise use JPG or PNG but want smaller files.

AVIF — the next-generation compression champion

AVIF is the newest mainstream format and currently the compression leader, often beating WebP by another 20% or more at the same quality. It supports transparency, HDR and wide colour. Browser support is now strong (Chrome, Firefox, Safari) though slightly behind WebP.

Why use it: the smallest high-quality files available today — ideal for image-heavy sites where speed is critical.

Watch out for: encoding can be slower, tooling is less universal, and the oldest browsers don't support it — so serve it with a WebP or JPG fallback.

When to use AVIF: performance-focused websites that can provide a fallback, large photo galleries, and hero images where every kilobyte counts.

GIF — animation's ageing veteran

GIF is an old lossless format limited to just 256 colours per frame. It's famous for short looping animations, but that low colour limit makes photos look terrible and the files surprisingly large.

Why it's still around: universal support and simple looping animation with basic transparency.

Watch out for: only 256 colours, large files, and poor quality for anything photographic.

When to use GIF: honestly, rarely. For animation, an animated WebP or a short MP4/WebM video is far smaller and sharper. Reach for GIF only when a platform specifically requires it.

SVG — infinitely scalable vector graphics

SVG is not pixels at all — it's XML code describing shapes, paths and colours. That means it scales to any size with zero quality loss and stays tiny for simple graphics. It's the gold standard for logos, icons and illustrations on the web.

Why use it: perfectly sharp at any resolution (great for retina screens), tiny files for simple art, editable in code, and styleable with CSS.

Watch out for: it cannot represent photographs, and complex SVGs can become heavy. Because it's code, only use SVGs from sources you trust.

When to use SVG: logos, icons, simple illustrations, and anything that must look crisp at every size.

Other formats you'll occasionally meet

TIFF — a lossless, high-quality format used in professional printing and archiving; files are huge and it isn't meant for the web. BMP — an old, uncompressed format with enormous files; avoid unless a legacy tool requires it. HEIC/HEIF — Apple's efficient format for iPhone photos; great compression but limited support, so convert to JPG or WebP before sharing widely. RAW — the unprocessed sensor data from a camera; perfect for editing, but you must export to JPG/PNG/WebP to share.

Image format comparison at a glance

How to choose: a 30-second decision guide

• Is it a logo or icon that must scale? Use SVG.
• Does it need a transparent background? Use PNG, or WebP for smaller files.
• Is it a photograph for a modern website? Use WebP or AVIF (with a JPG fallback).
• Is it a photograph that must open anywhere? Use JPG.
• Is it a screenshot, chart or flat-colour graphic? Use PNG (or WebP).
• Do you need animation? Use animated WebP or an MP4 video instead of GIF.

Frequently asked questions

Which is better, JPG or PNG?

Neither is universally "better" — they're built for different jobs. Use JPG for photographs because it produces much smaller files, and PNG for logos, graphics, screenshots and anything needing transparency or perfectly sharp edges.

Should I use WebP instead of JPG and PNG?

For modern websites, usually yes. WebP files are roughly 25–35% smaller at the same quality and support both transparency and animation. Keep a JPG or PNG fallback if you must support very old browsers or certain print tools.

What is the best image format for a website?

WebP (or AVIF) for photos and most images, PNG when you need transparency without WebP support, and SVG for logos and icons. These give the smallest files and the fastest page loads.

Does converting an image reduce its quality?

Converting to a lossless format like PNG keeps full quality. Converting to a lossy format like JPG or WebP re-compresses the image, so some detail is lost — though at high quality settings the difference is usually invisible.

Why is my PNG photo so large?

PNG is lossless, so it can't use the detail-discarding tricks that make JPG small. For photographs, converting the PNG to JPG or WebP can cut the file size dramatically with little visible difference.

Which format keeps a transparent background?

PNG, WebP, AVIF and SVG all support transparency. JPG does not — a transparent area saved as JPG turns white or black.